The main objective of the proposed research is to further our understanding of the molecular events controlling the biosynthesis of peptide hormones. The proposed studies focus on the isolation and characterization of the mRNA for the antral hormone gastrin. To isolate homogeneous mRNA from human gastrinoma tissue (Zollinger-Ellison syndrome) and hog antral mucosa, deoxyoligonucleotides complementary in sequence to the mRNAs will be chemically synthesized. The synthetic oligonucleotides will be used as hybridization probes to detect gastrin specfic mRNAs and will also be covalently coupled to cellulose for use in purifying the mRNAs by affinity chromatography. The physical properties of the isolated mRNAs will be studied and nucleotide sequence analysis will be carried out to identify the coding and noncoding regions of the messages. In addition, the initial translation products synthesized from these mRNAs in vitro in the wheat germ ribosomal system will be isolated and characterized.